Footwear and Method of Manufacturing Same

ABSTRACT

A footwear article is formed by providing at least one spent automobile tire having a tread, separating a portion of the tread of the tire, trimming the separated portion into the general shape of a foot and securing the separated portion to a top sole portion. The bottom sole portion of the footwear article has a generally, non-uniform thickness and irregular pattern. The bottom sole portion can fixer have elements of a scrub pattern indicator element, a tie bar indicator and/or a ply fragment visible on an outer edge thereof.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present invention claims the benefit under 35 U.S.C. §119(e) of U.S. provisional patent application No. 60/894,247, filed Mar. 12, 2007 and entitled “Footwear and Method of Designing and Manufacturing Same,” the disclosure of which is hereby incorporated by reference in its entirety.

FIELD OF THE INVENTION

The present invention relates to footwear, and more particularly to footwear articles such as a casual sandal or flip-flop type article incorporating recycled tire tread, pairs of such articles as well as a method for manufacturing same.

BACKGROUND OF THE INVENTION

Spent tires (i.e., used, worn or scrub tires) do not biodegrade and are often disposed of in landfills. Such disposed tires can catch fire or house mosquitoes, rats and other disease-bearing pests. The fraction that are salvaged are mostly burned as fuel, for industrial uses or in electricity generation—a waste of high quality rubber that should and could be re-used. While typical passenger tires can last for 50,000 or more miles, tires used in professional auto racing can become worn and spent after only 100 miles of racing. What is needed is a way to turn this rubber waste into a desirable product.

SUMMARY OF THE INVENTION

The present invention takes scrub tires received from various collection areas and processes them into useful footwear articles. An example collection area is a race track and/or speedway venue, where automobile races occur and where large numbers of tires are quickly spent. The collected scrub tires are transported to a suitable processing center, where the tires are cut, punched and/or stamped to form portions of footbeds which act as bottom sole members for footwear articles. As scrub tires from an auto race can have varying degrees of wear, the bottom sole members of each footwear article according to the present invention can have varying bottom sole thicknesses or depths along with irregular patterns, even as between two footwear articles in the same pair. In one embodiment of the present invention, a top sole portion and a bottom sole portion are secured together to form a footwear article, wherein the bottom sole portion has a generally non-uniform depth and irregular pattern. In addition, the present invention provides footwear having a corded appearance as a result of ply fragments extending from the processed scrub tires in the manufacturing process according to the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a front right perspective view of one embodiment of a footwear article according to the present invention.

FIGS. 2A and 3A are bottom schematic views of a pair of footwear articles incorporating designs on the bottoms thereof.

FIGS. 2B and 3B are right side schematic views of the leftmost article shown in FIGS. 2A and 3A, respectively.

FIG. 4 is a flow diagram representing one process in accordance with the present invention for making a footwear article.

FIG. 5 is a cross-sectional view of a tread and tread tie bar indicator;

FIG. 6 is a cross-sectional view of a tread and a tread wear indicator molding device;

FIG. 7 is an illustration of different wear indicator designs;

FIGS. 8 and 9 are a bottom schematic view of illustrative pairs of footwear articles in accordance with the present invention.

FIGS. 10A through 10C are side views of top and bottom sole portions of different embodiments of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

As shown in FIG. 1, one embodiment of the present invention comprises a footwear article 10 having a footbed 12 comprising a top sole portion 14 and a bottom sole portion 16. A strap member 20 can be secured to the top sole portion 14, or to both the top 14 and bottom 16 sole portions. The strap member 20 can have a front toe divider element 22 that extends through an opening 25 in the top sole portion, or openings in the top 14 and bottom 16 sole portions. In one embodiment of the present invention, the front toe divider element 22 has a securing post (not shown) that helps prevent the element from slipping back through the opening 25 and becoming detached from the footbed 12. The strap member 20 further includes side supports 30, 32 that retain the user's foot atop the footbed 12. The side supports 30, 32 extend from the divider element 22 to opposite sides 17, 18, respectively, of the footwear article 10, and are secured to the top sole portion by stitching, glue or other known bonding method. Similarly, the top sole portion can be secured to the bottom sole portion by stitching, glue or other known bonding method.

In one embodiment of the present invention, for example, one or more intermediate sole members are positioned in between the top 14 and bottom 16 sole portions. The intermediate sole member can be provided for additional comfort, height, fashion or other reason. In such an embodiment, the top sole portion 14 and bottom sole portion 16 are not in direct contact, yet remain secured via the intermediate member.

The top sole portion 14 can be formed of any suitable material for footwear such as sandals, for example, as contemplated by the present invention. Materials such as leather, ethyl vinyl acetate (EVA) and rubber are known materials for such purposes. The bottom sole portion comprises rubber material separated from a spent or scrub tire and can therefore have a generally, non-uniform thickness and irregular pattern that can differ from one footwear article to the next, even within the same pair. The non-uniform thickness and irregular pattern are provided as a result of being separated from a spent or scrub tire, and not from being specially formed from a uniform block of rubber material, for example. Automobile racing tires, such as those used in connection with NASCAR® sanctioned events, are suitable candidates for use with the present invention.

When racing tires are spent, the wear on the tread or tire outer surface (see 17 in FIGS. 1 and 4) can be uneven, resulting in a bottom sole portion that has a substantially and generally non-uniform and irregular thickness. New racing tires may be provided, for example, with a tread or tire outer surface thickness of perhaps only 3/32 inch. When the tire is used during a race, this thickness can be worn to perhaps 1/16 inch or even 1/24 inch, which while dangerous is also understood to be within suitable tolerances given the smooth racing surfaces and lack of debris on today's tracks. Nevertheless, each tire can receive a different level of wear, abrasion and graining, which makes for unique bottom sole portions on footwear articles provided according to the present invention.

The cross-section of a typical tire reveals an outer tread or tire surface, an optional cap ply layer, one or more belt layers (such as steel belts, for example), one or more radial or bias body layers and an optional inner liner layer built over a bead bundle. The cap, belt, body and liner layers are comprised of different types of fabrics, such as polyester cord, for example. The layers are typically called plies. The cords in a radial tire run perpendicular to the tread, while the cords in a bias-ply tire run diagonally to the tread. The plies are coated with rubber to help them bond with the other components and to seal in the air. A tire's strength is often described by the number of plies it contains. Whereas a typical passenger car tire has two body plies, racing car tires have many more to accommodate the high heat and speed experienced in racing conditions.

Racing tires are also provided with much thinner tread or outer surface 17 than standard passenger vehicle tires and are typically “slicks” in that they are not provided with typical tire tread blocks and grooves of standard passenger vehicle tires, because they are not meant to be raced in wet conditions. With the advancement of technology and investment in racing, tires are being manufactured specifically for use with certain tracks, temperatures, distances and racing conditions, for example. Since slicks have greater surface area contact with the race track, they provide greater traction and control to the driver. Because they are so thin and flat, however, racing tires are not capable of being driven for long distances without blowing out. In many cases, racing tires are only capable of going roughly one hundred miles before needing replacement. During the time that racing tires are operable, they generate tremendous heat and become sticky, often picking up minute articles of debris that may have found their way on to the race track, or may have been kicked off another car tire, bounced up against the outer wall of the race track and deflected back onto the track driving area. Additionally, because many automobile races involve an oval-shaped track requiring drivers to turn left at every corner, the tires are worn in an uneven manner.

Graining, for example, can be caused by racing or by overworking the tires before getting them up to a working temperature. Once a graining pattern is worn into the surface of a tire, it can be difficult to wear the pattern away. The ridges tend to perpetuate as wear continues. The graining is generally not present across the entire tread or outer surface, which results in an irregular pattern across a given section of tire tread or tire outer surface.

Abrasion is generally initiated by local stress concentrations at the contact between track debris or rough spots and rubber. Abrasion patterns can appear as an array of nearly parallel ridges at right angles to the abrasion direction, for example. The shape of the ridges in cross section can be saw-toothed, for example, with the teeth pointed against the direction of abrasion. During sliding, for example, deflection waves in the rubber turn into peaks which are bent over, exposing the upstream side to abrasion. The peaks can be worn into teeth with tips that eventually wear off. Abrasion intensity usually depends on shape rather than size of the track rough spots. Abrasion, like graining, results in an irregular pattern across a given section of tire tread, and farther results in non-uniform wear that can cause tire tread or outer surface thickness to vary across a given section.

FIGS. 2A and 3A illustrate what might be found on the bottom of a pair of traditional commercially available sandals or flip flops. As shown in FIG. 2A, there is a regular pattern of ridges 45 formed into the bottoms 46 of the footwear articles. Such a pattern might be found on a pair of sandals worn by a user who prizes traction, for example. The pattern on the left article 47 is repeated on the right article 48 to provide even support and traction to each foot of the user. FIG. 2B is a right side view of the left most article 48 (for the right foot) shown in FIG. 2A, whereupon the extension of the ridges 45 can be seen. The bottom soles of the footwear articles in FIG. 2A further have a uniform thickness and average depth, even with ridges. While the thickness/depth of the bottom sole measured from the peak of one of the ridges would be greater than the thickness/depth of the bottom sole portion measured from a valley between ridges, the thickness would be uniform and/or consistent throughout the footwear articles, in newly made form. The bottom sole of the left article has the same average depth as the bottom sole of the right article. If these articles in FIG. 2A were provided without ridges, but instead with a flat bottom sole portion, they would also have a uniform thickness and uniform average depth in newly made form.

As shown in FIGS. 3A and 3B, there is an arch support element 51 formed into the bottom 52 of the footwear article. The pattern on the left article 53 is repeated on the right article 54 such that each foot of the user receives the same type of support. FIG. 3B is a right side view of the left most article 54 (for the right foot) shown in FIG. 3A, whereupon the arch support element 51 can be seen. Thus, the pair of articles in FIGS. 3A and 3B has a regular pattern and a uniform average depth in new form.

FIGS. 8 and 9 show illustrative schematic views of the bottom surfaces 16 of footwear articles 10 of the present invention, which may be formed in accordance with the method steps shown in FIG. 4. As shown in FIG. 4, a tire 70 such as a scrub racing tire is provided and a portion 72 of the tire tread/outer surface and ply element(s) (all indicated at 71) is removed. This portion can be removed by cutting with a cutting tool suitable for cutting tire rubber such as a water jet cutting tool, for example. It will be appreciated that the removed tire portion will have areas of uneven wear, and thus will have an irregular pattern and non-uniform thickness or depth throughout. The removed tire portion can then be further trimmed into a footbed pattern using a pattern cutting tool represented at 74. In one embodiment of the present invention, the pattern cutting tool is a die in the general shape of a footbed which can be stamped or punched down onto the tire tread portion to remove the exterior elements of the tire tread portion. In another embodiment of the present invention, a multiple-axis router with a cutting edge can be used to trim the raw tread portion. In another embodiment of the present invention, a water jet cutting tool is employed. Once trimmed, the footbed bottom sole portion 16 is then available for securing to the remaining footwear article parts. As shown in FIG. 4, a strap member 20 and top sole portion 14 can be secured together with bottom sole portion 16 to form a footwear article 10.

As shown at the bottom of FIG. 4, and further shown in FIG. 8, bottom sole portion 16 can have an outer surface 17 with multiple areas having a different thickness (e.g., 16 a, 16 b, 16 c, 16 d, 16 g) based on being trimmed from a spent tire. These areas 16 a-k have different thicknesses because the tire outer surface or tread surface 17 has been worn in a non-uniform way. FIG. 8 shows how a pair 10 of footwear articles can be provided wherein the bottom sole portion 16 of each article has a different pattern, a different average depth or thickness and therefore a different supportive feel from the matching and opposite footwear article. Specifically with regard to FIG. 8, it can be seen that the bottom sole portion 16 of the left foot article 81 has four different sections having different thicknesses. For example, area 16 h has a different thickness from area 16 i, 16 j, and 16 k. In the embodiment where a spent racing tire is employed in constructing the bottom sole portion of the present invention, the range of thicknesses of the outer element of the bottom sole portion might be between 1/24 and 3/32 of an inch, inclusive, for example. The outer element (see 17 in FIG. 1) of the bottom sole portion corresponds to the tread surface or outer surface of the tire being used. The bottom sole portion includes this outer surface as well as the ply and other tire elements described herein.

Each of areas 16 h, 16 i, 16 j and 16 k can be a different thickness within the 1/24- 3/32 inch range, for example. Similarly, each of areas 16 a, 16 b, 16 c, 16 d, 16 e, 16 f and 16 g in the right foot article 83 can have a different thickness, or even the same thickness separated by a different thickness. For example, elements 16 a and 16 b in FIGS. 4 and 8 can have the same thickness separated by element 16 c. With each foot article bottom sole portion having a non-uniform thickness and irregular pattern, it will be apparent that each article in a pair of articles will be unique in terms of its average thickness and exact density. This is counterintuitive to shoe and footwear article manufacturing techniques, where tremendous stress is placed on giving users uniform traction, support and patterns on the bottom soles of both shoes within a given pair.

The footwear article provided in accordance with the present invention can also include unique patterns visible on the sole bottom portion thereof as a result of employing scrub tires having different objects embedded or formed therein. As shown in FIG. 5, for example, a cross-sectional view of a tire 80 shows a plurality of tread blocks 82 having a groove 84 formed therein. Such a tire would more commonly be found on a passenger vehicle requiring a tread design suitable for wet weather. A wear indicator, scrub indicator and/or tie bar indicator 86 is molded into the tire during formation, and gives a tire inspector (e.g., driver, service station attendant, etc.) a visual indicator to use in evaluating whether the tire needs to be replaced. When the top surface 85 of the tread block(s) reaches the level of the scrub indicator 86 (i.e., the tread block is flush with the scrub indicator), then the inspector knows that the tire is spent.

As shown in FIG. 6, for example, a similar arrangement of tread blocks 82 and grooves 84 is shown in the tire cross-section 80. However, instead of the tie bar indicator 86, a scrub pattern indicator element is formed by a tire-injectable molding device 90. The molding device 90 includes an injectable tube 92 having one or more patterns impressed therein such that, when the tire is being cured, the rubber forms around the pattern(s) and thereby leaves a hollow impression in the tire tread. As an example, the tube 92 can have a bottom segment pattern used in connection with warning the inspector that the tire needs to be replaced (see, e.g., the “X” pattern indicator element 94 in FIG. 7). The tube 92 can further have an upper segment pattern to inform the inspector that the tire is maintaining satisfactory tread depth (see, e.g., the check mark pattern indicator element 96 in FIG. 7). Any of a number of patterns can be ingrained in the tire tread, and it is not necessary for the tire tread to have grooves or other water handling channels in order to incorporate such patterns. Thus, a slick tire without tread grooves can be provided with scrub pattern indicator elements as described above.

FIG. 9 shows an example pair of bottom sole members of footwear articles in accordance with the present invention. As the tire tread is cut according to the methods described above and shown in FIG. 4, for example, the tread may include one or more of the pattern indicator elements 94 and 96 as shown. Such pattern indicator elements then appear on the bottom of the bottom sole member and contact the ground during use of the footwear articles, much like the racing tire. In one embodiment of the present invention, the pattern indicator element can change over the length of use of the footwear article. As an example, the check mark pattern indicator elements 96 of the left-most footwear article in FIG. 9 may turn to the “X” pattern indicator elements 94, as shown by way of example in the right-most article in FIG. 9.

FIGS. 10A through 10C are example side views of the top 14 and bottom 16 sole portions in accordance with other embodiments of the present invention. FIG. 10A shows the bottom sole portions with differently sized ply fragments or threads 102, 104 on the outer edge 101 of the bottom sole portion 16 so as to be visible. Such fragments 102 can be seen in the article 10 shown in FIG. 1, for example. FIG. 10B shows the bottom sole portion with only the larger sized ply fragments 102, and FIG. 10C shows the bottom sole portion with only the smaller sized ply fragments 104 shown on the outer edge thereof. The ply fragments are visible because they are in the cut line when the spent tires are cut to form the bottom sole portions. The ply fragment pattern depends upon the type of material used in the tire for the various plies, as described above. The pattern associated with a bias-ply tire will therefore be different from the pattern associated with a radial ply, for example.

The invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the claims of the application rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein. 

1. A pair of sandals, comprising: a first footwear article for a left foot having a top sole portion and a bottom sole portion secured together, wherein the bottom sole portion comprises rubber material separated from a scrub tire and having a first average thickness; and a second footwear article for a right foot having a top sole portion and a bottom sole portion secured together, wherein the bottom sole portion comprises rubber material separated from a scrub tire and having a second average thickness, with the second average thickness being different from the first average thickness.
 2. The pair of sandals of claim 1 wherein the scrub tire is an automobile racing tire.
 3. The pair of sandals of claim 1 wherein at least one of the footwear articles includes at least a scrub pattern indicator element.
 4. The pair of sandals of claim 1 wherein the bottom sole portions each include an outer edge and wherein at least one of the footwear articles includes a ply fragment visible on the outer edge of the bottom sole portion thereof.
 5. A footwear article, comprising: a top sole portion; and a bottom sole portion secured to the top sole portion, the bottom sole portion comprising rubber material separated from a scrub tire and having a ply fragment visible on an outer edge thereof.
 6. The article of claim 5 wherein the bottom sole portion includes at least a portion of a scrub pattern indicator element visible thereon.
 7. The article of claim 5 wherein the bottom sole portion has a generally non-uniform thickness as a result of being separated from the scrub tire.
 8. A method of manufacturing a footwear article, comprising: providing at least one scrub automobile racing tire having a tread; separating a portion of the tread of the tire, and trimming the separated portion into the general shape of a foot; and securing the separated portion to a top sole portion.
 9. The method of claim 8 wherein the tread is of generally non-uniform thickness.
 10. The method of claim 8 wherein the tread has a thickness of less than or equal to 3/32 inch.
 11. The method of claim 8 wherein the separated portion is a bottom sole portion having a ply fragment visible on an outer edge thereof.
 12. The method of claim 8 wherein the separated portion is a bottom sole portion having at least a portion of a scrub pattern indicator element visible thereon.
 13. A footwear article, comprising: a top sole portion; and a bottom sole portion secured to the top sole portion, the bottom sole portion comprising rubber material separated from a scrub tire and having at least a portion of a scrub pattern indicator element visible thereon. 